Submerged dredging device with air filled hood



SUBMERGED DREDGING DEVICE WITH AIR FILLED HOOD Dec. 15, 1964 J. c. sKAKEl.

SUBMERGED DREDGING DEVICE WITH AIR FILLED HOOD 2 Sheets-Sheet 2 Filed June 20. 1962 m-mL f7? Mezz Zo 7".' Jaynes T'kakel United States Patent O 3,166,966 SUBMERGED DREDGING DEWCE WITH FILLED H001) llames C. Skakel, Greenwich, Conn.

(277 Park Ave., New York 17, NX.)

Filed .inne 20, 1962, Ser. No. 203,861 Claims. (Cl. 37-60) This invention relates to a new Aand improved dredging device .or system for mining alluvial deposits, land reclamation and filling, channel construction and maintenance, and to sand and gravel production.

It is a' particular object of this invention to move Water-bound solids at high speed with high efficiency and at low cost. It is still another object of this invention to accomplish the foregoing at great depths or if so desired, at shallow depths.

This invention incorporates many of the features of the dredging dev-ice described in US. Patent 3,010,232, entitled Excavating Dredging, Raising, and Trans-mib ting Earthy and Other Loose Matter and issued November 28, 1961, of which I am a co-inventor; but the present invention represents an improvement thereover with respect to certain features.

For a complete understanding of the present invention, reference should be had to the lattached drawings, FIG- URES 1 and 2, which correspond approximately to FIG- URES l, 10, and l2 of said patent but which also illustrate the improvements over the aforesaid patented device.

FIGURE 1 is an -elevational View of a typical dredging system employed in the present invention.

FIGURE 2 is a detailed elevational view`of the sub` merged digging unithood-hopper assemblage of the present invention, said assemblage also being shown partly in section.

T-he dredging device comprises at least one relatively short endless chain of buckets 2 driven by a suitable prime mover (not shown but illustrated, and also described in several places in said US. Patent 3,010,232, such as at column 2, line 6, column 3, line 8, and column 6, line 23) such as an electric motor or a diesel engine provided with a ventilation or breather pipe, said prime mover being enclosed in a watertight compartment 4. This assemblage is suspended under water by suspension cables 5 from a derricl: 6 or similar device on a surface supporting unit or element 7 such as a barge or float onthe surface of the water; or it may be similarly suspended from a dock or other stationary type support.

The digging buckets empty into a hopper 8, which typically possesses some of the, features such as illustrated or described in the hoppers of U.,S. Patent 3,010,- 232. The hopper has a materials receiving area 8a and a mixing or dispersing area 8b where the solids deposited in the hopper by the digging buckets are acted upon by a stream of water from one or more high speed hydraulic jet nozzle-type inlet openings 10 for the purpose of helping to disperse the solids uniformly into an aqueous slurry or pulp stream. The hopper .alsoV possesses a venturi-shaped discharge opening or exit means 11 substantially opposite said nozzle-type inlet to -assist in controlling the velocity of the hydraulic jet slurry stream and in effecting the pick-up and transfer of the slurry.

On the aforesaid dock, barge or other surface supporting facility 7 there is` provided, as previously mentioned, a hoist or derrick 6 for positioning the digging unit and hopper assemblage by means of cables 5. (The digging unit comprises the buckets 2, the submerged encased motor and the water-tight compartment 4.) The Vdigging unit and the hopper are each supported by a 3,1%,966 Patented nee. 1s, 1964 base supporting unit 12 which rests on the floor of the aqueous body being dredged. The desired relative positioning and angle of the digging unitl with respect to the hopper is achieved and maintained by the cables 5 and supports such as 13.

An air-tight hood 14 open at the bottom and closed v have a shape such as illustrated in the drawing, although many shapes and sizes are feasible. The use of thisv hood in the present dredging device constitutes a very important aspect of this invention and will be discussed in more detail hereinafter.

Also on the aforesaid barge, dock, etc., there are additionally provided a power unit 1S such as a diesel electric generator, an air compressor 19, a suction pump 253 and: a water pump 21.

Operatively connected to the foregoing units .are conneet-ing lines, pipes or cables to the sub-merged units. These are: air line 22 between the air compressor 19 and the :hood 14; electric cable 23 between the power unit 18 and the enclosed submerged motor; suction line or pipe 24- between the suction pump 20 and the venturioutlet 11 of the hopper; and water line 25 between Water pump 21 and the jet-nozzle inlet 10 of the hopper.

Water pump 21 draws water by means of suction hose 26 from the aqueous body being dredged and has sufficient capacity to pump water at the desired velocity through water line 25, jet-nozzle 1l), hopper 8, Venturiexit means 11 and suction line pipe 24, and which either alone or in combination with suction pump 20 has sucient capacity to pump the slurry of solids and water through discharge pipe 24a to the desired point of discharge.

Air compressor 19 has a requisite volume and pressure capacity to supply compressed air by air hose 22 through orifice 33, to the inner part of hood 14 at sufficient pressure to keep the water level within said hood just slightly above its bottom edges and to maintain a substantial air space within said hood between its top and sides and the desired water level. Suflicient air space is maintained within said hood so that when the buckets invert over the hopper, the contents thereof have free fall through air for a substantial distance, such as 4 or 5 or more feet, before contacting water. Typical dimensions of hood lllfor sides A, B, C, and D are l5 feet, 9 feet, 3 feet, and 19.5 feet respectively. (The bottom of the hood is substantially rectangular shaped with side D and its opposite Wall being 19.5 feet in length, and the other legs of the rectangle being about l2 feet in length.)

Suction pump 20 is a conventional hydraulic dredge pump, through which solids are transmitted in the usual manner.

The power unit 18 can provide power for the suction pump and air compressor as well as. for the digging unit and may as aforesaid be an electrical generator-engine combination or it may be a diesel engine, or a steam engine, or an equivalent power source; -or the power may be derived from an outside source particularly if the dredging is carried out near shore from a dock.

It should of course be recognized that there are many possible combinations for provi-ding'the necessary power so long as the motor driving the digging unit is submerged along with the digging unit. For example, an engine, generator and a main motor may be placed on the surface unit to provide the power necessary to drive the water 'and air pumps and auxiliary devices such as Winches and anchors, etc., as Well as to provide electricity for cable 23 to drive the submerged motor. Or, with the same general overall setup, instead of a submerged electric motor, a diesel engine having a breather pipe to the surface of the Water may be employed. Or three submerged diesel engines all having breather pipes and all directly driving the compressed air, Water and digging units may be employed along with an auxiliary diesel engine on the surface to drive the surface units such as the Winches, etc. Submerged hydraulic motors may also be used as driving means for the digging buckets unit.

If the surface unit of the dredging system is a iioating facility such as a barge, it is providedl with sufficient Winches 30, anchors 31 and propulsion and steering devices (not shown) as are required to facilitate moving of the barge in such a manner that proper control of the digging facilities can be maintained.

Pipeline floats 32 are placed under discharge pipe 24a whenever the distances that the dredged material have to be pumped to the fill area Warrant or require the use of same.

In operation, sand and gravel or other water-bound solids excavated by buckets 2 are dumped by the buckets, through air within the hood into hopper 8, and fall to the bottom area 8b. Water from the river, or lake, or sea, surrounding hood 14 flows slightly up into the bottom of the pressurized hood, into the space between the hood and the hopper, and over the lower edge of the hopper at F and is drawn down into the bottom of the hopper by means of the vacuum created by the main suction pump 20 on the dredge through suction pipe 24, the open mouth of which is located at an outlet orifice from the hopper such as the discharge end of venturiopening 11. This suction pulls a mixture of water from F and sand or gravel from 8b into suction pipe 24 and thence up through suction pump 20 and out discharge line 24a. Auxiliary water is supplied to the bottom area 8b of hopper 8, through jet nozzle 10 and water pipe 25.

The apparatus of this invention can be used with any of the hoppers shown in U.S. Patent 3,010,232. It can also employ pneumatic acceleration, such as illustrated in FIGURE 3 of that patent, or special pipe conduits such also as illustrated and described therein. The present apparatus possesses or can achieve most of the advantages set forth in column 7 of the patent on the previous device, as Well as several additional advantages.

The hood improvement of this invention permits the digging buckets to be emptied in air instead of being completely immersed in water. This makes it easier to empty the buckets and also makes it more certain that the solids will fall into the hopper where desired, instead of partly being lost outside the hopper. The suction pump-suction hose improvement makes possible combination discharge techniques, viz, positive water pressure through jet nozzle along with suction by means of suction pipe 24 and suction pump 20. The combination of one or more of these features along with the features of the dredge device of U.S. Patent 3,010,232 results in a most efficient apparatus and also results in many novel and improved combinations and/or subcombinations. It should be appreciated that the hood improvement may be used without the suction improvement or vice versa; it should also be. appreciated that they can be employed together-and with or without the positive water pressure-jet nozzle and/or venturi-type discharge feature(s).

The invention can be operated successfully, employing a considerable range of sizes and designs of hoppers, digging buckets, discharge pipes, air and water pressures. In each case the hood must be of sufficient size to surround the digging buckets and hopper, and of suiiicient strength to withstand the air and water pressures to which the digging device is subjected.

More detailed information and structural features of the digging unit and buckets, etc., viz. of the apparatus of which the present invention is an improvement-may be obtained from a reading of the US. Patent 3,010,232 specification.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim:

l. In a dredging system which comprises in combina-' tion: (l) a surface supporting element; (2) means onf said surface supporting element for pumping water; and (3) means on and operatively connected to said surface supporting element for raising and lowering a dredging unit which is also operatively connected to said means; said dredging unit comprising an entirely submerged digging unit -comprising at least one endless chain of digging buckets operatively connected to a submerged driving motor encased in a substantially water-tight compartrnent and a collecting hopper separate from said digging unit and positioned in such a manner by mechanical supports and connecting members that the digging buckets discharge into a portion thereof; the lower' portion of said hopper comprising a mixing area having an inlet for receiving water under pressure from the water pump on said surface supporting element; and the lower portion of said hopper also having a venturi-discharge opening substantially opposite said inlet through which is formed an aqueous slurry of the dredged material dropped from said digging buckets, the improvement which comprises the addition of means on said surface supporting element for compressing air, and a pressurized air-tight hood, operatively connected tosaid means for compressing air, placed over the submerged digging unit and the hopper and attached thereto in such a manner that the material dug by the submerged digging buckets is enabled to fall freely through air prior to entering the hopper.

`2. in a dredging system which comprises in combination: (l) a surface supporting element; (2) a means on said surface supporting element for pumping water; and (3) means on and operatively connected to said surface supporting element for raising and lowering a dredging unit which is also operatively connected to said means; said dredging unit comprising an entirely submerged digging unit comprising at least one endless chain of digging buckets operatively connected to a submerged driving motor encased in a substantially water-tight compartment and a collecting hopper separate from said digging unit and positioned in such a manner by mechanical supports and connecting members that the digging buckets discharge into a portion thereof; the lower portion of said hopper comprising a mixing area having an inlet for receiving Water under pressure from the water pump on said surface supporting element; and the lower portion of said hopper also having a venturidischarge opening substantially opposite said inlet through which is forced an aqueous slurry of the dredgedA material dropped from said digging buckets, the improvements which comprise:

A. The addition of means on'said surface supporting element for compressing air, and a pressurized airtight hood, operatively connected to said means for compressing air, placed over the submerged digging unit and the hopper and atttached thereto in such a manner that the material dug by the submerged digging buckets is enabled to fall freely through air prior to entering the hopper; and

B. The addition of a suction pump on said surface supporting element, which pump is operatively connected to the venturi-discharge opening from said hopper, to assist in discharging 'the dredged material from said hopper.

3. A dredging system according to claim 2 wherein at least a portion of the top of the hopper is positioned beneath the lowest extent of the hood thereby permitting surrounding water to enter the hopper.

4. A dredging system comprising in combination: (1) a surface supporting element; (2) a water-suction pump on said surface supporting element; (3) means on said surface supporting element for compressing air; (4) means on and operatively connected to said surface supporting element for raising and lowering a dredging unit which is also operatively connected to said means; said dredging unit comprising an entirely submerged digging unit comprising at least one endless chain of digging buckets operatively connected to a submerged driving motor encased in a substantially water-tight compartment and a collecting hopper separate from said digging unit and positioned in such a manner by mechanical supports and connecting members that -the digging buckets discharge into a portion thereof; the lower, portion of said hopper having an orifice, operatively connected to said watersuction pump, through which orifice is forced an aqueous slurry of the dredged material dropped from said submerged digging buckets; and (5) a pressurized air-tight hood, opera-tively connected to said air compressing means, placed over the submerged digging unit and the hopper and attached thereto in such a manner that the material dug by the submerged digging buckets is enabled to fall freely through air prior to entering the hopper.

5. A dredging system according to claim 4 wherein at least a portion of the top of the hopper is positioned beneath the lowest extent of the hood thereby permitting surrounding water to enter the hopper.

References Cited in the le of this patent UNITED STATES PATENTS 503,655 Ellicott Aug. 22, 1893 2,006,037 Woodrui June 25, 1935 2,718,717 Collins Sept. 27, 1955 3,010,232 Skakel et al Nov. 28, 1961 FOREIGN PATENTS 1,001,075 France Oct. 17, 1951 

1. IN A DREDGING SYSTEM WHICH COMPRISES IN COMBINATION: (1) A SURFACE SUPPORTING ELEMENT; (2) MEANS ON SAID SURFACE SUPPORTING ELEMENT FOR PUMPING WATER; AND (3) MEANS ON AND OPERATIVELY CONNECTED TO SAID SURFACE SUPPORTING ELEMENT FOR RAISING AND LOWERING A DREDGING UNIT WHICH IS ALSO OPERATIVELY CONNECTED TO SAID MEANS; SAID DREDGING UNIT COMPRISING AN ENTIRELY SUBMERGED DIGGING UNIT COMPRISING AT LEAST ONE ENDLESS CHAIN OF DIGGING BUCKETS OPERATIVELY CONNECTED TO A SUBMERGED DRIVING MOTOR ENCASED IN A SUBSTANTIALLY WATER-TIGHT COMPARTMENT AND A COLLECTING HOPPER SEPARATE FROM SAID DIGGING UNIT AND POSITIONED IN SUCH A MANNER BY MECHANICAL SUPPORTS AND CONNECTING MEMBERS THAT THE DIGGING BUCKETS DISCHARGE INTO A PORTION THEREOF; THE LOWER PORTION OF SAID HOPPER COMPRISING A MIXING AREA HAVING AN INLET FOR RECEIVING WATER UNDER PRESSURE FROM THE WATER PUMP ON SAID SURFACE SUPPORTING ELEMENT; AND THE LOWER PORTION OF SAID HOPPER ALSO HAVING A VENTURI-DISCHARGE OPENING SUBSTANTIALLY OPPOSITE SAID INLET THROUGH WHICH IS FORMED AN AQUEOUS SLURRY OF THE DREDGED MATERIAL DROPPED FROM SAID DIGGING BUCKETS, THE IMPROVEMENT WHICH COMPRISES THE ADDITION OF MEANS ON SAID SURFACE SUPPORTING ELEMENT FOR COMPRESSING AIR, AND A PRESSURIZED AIR-TIGHT HOOD, OPERATIVELY CONNECTED TO SAID MEANS FOR COMPRESSING AIR, PLACED OVER THE SUBMERGED DIGGING UNIT AND THE HOPPER AND ATTACHED THERETO IN SUCH A MANNER THAT THE MATERIAL DUG BY THE SUBMERGED DIGGING BUCKETS IS ENABLED TO FALL FREELY THROUGH AIR PRIOR TO ENTERING THE HOPPER. 